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. 2024 Feb 14;9(8):9593-9602.
doi: 10.1021/acsomega.3c09403. eCollection 2024 Feb 27.

Investigation of the Structural Behavior of Reinforced Concrete Beams at Elevated Temperatures

Mahmud Yağan  1 , Fatih Mehmet Özkal  1 , Muhammed Orhan Öztürk  1 , Mehmet Polat  1
Affiliations

Investigation of the Structural Behavior of Reinforced Concrete Beams at Elevated Temperatures

Mahmud Yağan et al. ACS Omega. .

Abstract

Reinforced concrete structures encounter a range of detrimental external factors over their operational lifespan. One of them is the elevated temperature effect due to fires. Conversely, due to the influence of global warming, temperatures are on the rise worldwide, leading to an increase in fire incidents. Owing to the increasing rates of construction and fire incidents, it becomes imperative to investigate the durability of reinforced concrete members when exposed to high temperatures. This experimental study aims to assess the structural behavior of reinforced concrete beams following exposure to elevated temperatures. To accomplish this goal, concrete cube specimens, steel rebars, pull-out specimens, and reinforced concrete beams were exposed to elevated temperatures of up to 800 °C and then allowed to cool in air. Following this, all specimens were subjected to testing in accordance with the relevant codes and standards. Test results were analyzed through comparison. In a comprehensive examination of the results, it is evident that the concrete compressive strength experiences an approximately 55% reduction at 600 °C. Meanwhile, there is no notable decrease in the yield strength of the steel at this temperature. However, at 800 °C, steel yield strength decreases by nearly 30%, while the compressive strength of the concrete decreases by a significant 82%. This indicates a substantial reduction in the load-bearing capacity of the beam specimens due to concrete deterioration and the subsequent decline in the bonding performance between concrete and steel rebars.

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Conflict of interest statement

The authors declare no competing financial interest.

Figures

Figure 1
Figure 1
Compressive strength of concrete exposed to elevated temperatures.
Figure 2
Figure 2
Yield strength of steel exposed to elevated temperatures.
Figure 3
Figure 3
Pull-out sample coated with fire plaster and a sample ready for testing.
Figure 4
Figure 4
Pull-out test setup according to ASTM A944-10 guidelines.
Figure 5
Figure 5
Bond strength of steel exposed to elevated temperatures.
Figure 6
Figure 6
Reinforcement layout of the flexural failure group.
Figure 7
Figure 7
Reinforcement layout of the shear failure group.
Figure 8
Figure 8
Test setup for the beam specimens.
Figure 9
Figure 9
Residual strength values of concrete, steel, and bonding.
Figure 10
Figure 10
Flexural failure group after testing.
Figure 11
Figure 11
Load-bearing capacities of the flexural failure group.
Figure 12
Figure 12
Shear failure group after testing.
Figure 13
Figure 13
Load-bearing capacities of the shear failure group.
Figure 14
Figure 14
Load-bearing capacities of flexural and shear failure groups.
See this image and copyright information in PMC

References

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